In the past and at present, there are three methods for treating hydrocarbon contaminated soils, namely, incineration, bioremediation and soil washing. Incineration has the inherent cost disadvantages of high energy costs and transporting the soil to and from a usually remote incinerator. Bioremediation has the inherent disadvantages of low throughput, sensitivity to changes in temperature, uneven results and the extended period of time required to complete remediation. Most common soil washing techniques use surfactants to float out the hydrocarbons into the wash water requiring costly continuous water treatment to extract the hydrocarbons from the aqueous phase and have difficulty in reducing contamination to regulatory limits. Conventional soil washing, if it works, has a limited production volume.
Due to the high cost of cleaning contaminated soil, there exists throughout the United States millions of tons of soil contaminated with hydrocarbons located within such installations as oil refineries, industrial plants, airports, motor vehicle repair shops, auto service stations and military training areas.
Accordingly, there is a need for a high volume low cost method of efficiently removing hydrocarbons from contaminated soils.
There is also a need for a method of removing hydrocarbons from contaminated soils with portable equipment that can be moved from one contaminated site to another.